'unexpectedly-built' originates from the combination of 'unexpectedly' and 'built'. 'Unexpectedly' comes from 'unexpected', which is derived from the Latin 'ex-' meaning 'out of' and 'pectare' meaning 'to look'. 'Built' is the past participle of 'build', which comes from the Old English 'byldan', meaning 'to construct'.

'unexpectedly' evolved from the Middle English 'unexpectid', and 'built' from the Old English 'byldan'. Together, they form the modern English term 'unexpectedly-built'.

Initially, 'unexpectedly' meant 'not foreseen', and 'built' meant 'constructed'. Together, they describe something constructed without prior anticipation.